1. Field of the Invention
This invention relates generally to a method for system access in wireless networks. More particularly, the invention provides a method that may be practice at a wireless device for accessing a wireless network in a way that conserves a link cost at the wireless device. The invention is particularly well suited for use in Personal Digital Assistants, mobile communication devices, cellular phones, and wireless two-way communication devices (collectively referred to herein as “wireless devices”). The invention provides utility, however, in any device or system that accesses a wireless network.
2. Description of the Related Art
Techniques for accessing wireless networks are known. One such access technique is used in current COMA (Code Division Multiple Access) networks. In a typical access technique, a wireless device probes a base station at a given power level. If the base station does not respond, subsequent probes are sent to the same base station, typically escalating in power level, until either a response is received from the base station, or the wireless device declares an access failure.
U.S. Pat. No. 5,345,596 discloses a communication access system. A communication unit 10 (preferably, a radio telephone headset) is operable to communicate with one or more base stations. The communication unit 10 transmits channel requests at increasing signal strengths requesting a communication channel. The first channel request signal has a power level that is a predetermined fraction of the maximum output of the communication unit 10, and subsequent channel requests are transmitted at an incrementally higher power level.
Document WO-A-0126411 describes a hand-off system for a cellular telephone system comprising a plurality of mobile phones and base stations. Communication between a mobile phone and more than one base station is facilitated by timeslots selected in order to accommodate imitations of the mobile telephone equipment. Handover connection to another base station and disconnection from a current base station may also facilitated by determining a level of communications quality with respect to the base stations.